Improvement in engines for rock-drills



UNITED STATES PATENT OFFICE.

JAMES BRANDON AND ALBERT W. TRANKLE, OF NEW YORK, N'. Y.

IMPROVEMENT IN ENGINES FOR ROCK-DRILLS.

Specification forming part of Letters Patent No. 157,674,v dated December 15, 1874; application tiled March 7, 1874.

To all whom it may concern:

Be it known that we. JAMES BRANDON and ALBERT W. TRANKLE, of the city, county, and State of New York, have invented a new and Improved Steam-Engine for Rock-Drills; and we do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawing forming a part of this specification, in which- Fignre l represents a vertical longitudinal section; Fig. 2, a plan; Fig. 3, a vertical crosssectional view, and Fig'. 4 an end view.

The invention will first be fully described, and then pointed out in the claim.

A represents the cylinder, B the valve-rod, B' the valve, C the VaIVechest, and D the piston-rod, of engine. The valve-rod B has collars F, that secure the valve in place, and extensions E, on which are fixed the pistons G G. The guide ends g g ot' the pistons G work in the spaces R" R"'. H K are the steam-passages that connect each end of cylinder A with the steam-chest, and enable the piston M P N to be reciprocated. This piston has annular grooves M1 Mz and N1 N2, connected by longitudinal grooves O, (or simply recessed between the heads M P and P N.) The channel-ways thus formed between these heads connect with passage H byppening L, with channels Q. that lead to R" R'f',` by passages R R', and with the livesteam chamber C by passages S S'. Y

There is, in consequence of this relative construction, an equilibrium of steam-pressure always maintained on both sides of the pistons G G, except just before the heads M N reach the limit of their throw. The steam is momentarily cut oft from access to passage 'R through passage S, and the steam in end R"' is discharged through passages Q, R, O, L, and H into the exhaust. This serves to reverse the position of pistons G G and the valve B'. Ordinarily the live-steam chamber is always connected with spaces R" R"' behind pistons G G, either by way of passages S, S', H, O, R or R', and Q, or, when 'S is out ofi', through L, H, O, R or R', and Q. The steam is exhausted alternately through the passages H H.

Having thus desciibed our invention, what we claim is The combination, with piston having grooves O between its heads M N P, and the cylinder A, having steam-passages H, L, R, R', S, S', and Q Q, connecting with live-steam chamber O, of the connected valve-pistons G G, having spaces R" R"', connecting with said channelways Q, as and for the purpose specified.

JAMES BRANDON.

ALBERT W. TRANKLE. 

